| Maxdamantus | Hmm.. Wonder if anyone's thought of just sticking an N900 on the back of another phone case, as a slide-out keyboard. | 11:00 |
|---|---|---|
| bencoh | sounds ... bulky | 11:00 |
| bencoh | how would you connect those together? (bluetooth?) | 11:01 |
| Maxdamantus | USB. | 11:01 |
| KotCzarny | what is the interface of n900's kb? | 11:02 |
| KotCzarny | i2c? | 11:02 |
| Maxdamantus | I think so, but I'd be inclined to just run Linux on the N900 and connect using USB. | 11:02 |
| Maxdamantus | Maybe it'd be possible to run off the other device's power too, so wouldn't need a battery in the N900. | 11:03 |
| KotCzarny | still, bulky as heck | 11:05 |
| Maxdamantus | Actually, dunno if it's possible to boot the N900 without a battery. | 11:07 |
| bencoh | not really iirc | 11:07 |
| KotCzarny | n810 also has a kb | 11:09 |
| Maxdamantus | Seems to be possible at least to go from u-boot to Linux without a battery. | 11:09 |
| bencoh | Maxdamantus: does it manage to boot afterwards? | 11:10 |
| bencoh | I'm not certain the usb supply is enough to provide for the current peaks at boot | 11:11 |
| Maxdamantus | When I tried it just now it didn't boot all the way into the Maemo GUI, but dunno if that's because it was playing dead or if it "crashed" in some way due to lack of power supply. | 11:12 |
| Maxdamantus | But it was certainly running in userspace. | 11:12 |
| bencoh | neat | 11:13 |
| Maxdamantus | I wouldn't expect to run Maemo in the setup I'm thinking of. I would just run some init script that loads g_ether, configures some networking on it, and run something else that the main phone could connect to. | 11:14 |
| bencoh | yeah | 11:14 |
| Maxdamantus | This is 3.14 booted from u-boot without battery: https://i.imgur.com/dBOJA9a.jpeg | 12:36 |
| Maxdamantus | (still needed a battery in it for the initial boot) | 12:37 |
| Maxdamantus | I think I was originally in Maemo, with USB plugged in. Removed battery and the device rebooted into u-boot (with backlight off). | 12:39 |
| Maxdamantus | Dunno if the reboot was because of lack of power or some watchdog .. or maybe bme triggers a reboot when the battery voltage drops. | 12:40 |
| Maxdamantus | Seems to stay on indefinitely anyway in 3.14 after loading the twl4030 watchdog module. | 12:42 |
| Maxdamantus | (not in R&D mode) | 12:42 |
| Maxdamantus | Wonder what would happen if 5 V were just supplied across the battery terminals. | 12:56 |
| KotCzarny | read the specs of battery chip? | 12:57 |
| Maxdamantus | I imagine it's more than just the battery chip. | 12:58 |
| Maxdamantus | There must be something else in the N900 that decides when to boot | 12:58 |
| KotCzarny | but you can fry the chip | 12:59 |
| Maxdamantus | When the device is powered off and it's plugged into USB, it seems to put 1 V across the battery terminals. | 12:59 |
| Maxdamantus | Something must detect when that rises above some threshold, and it boots. | 12:59 |
| Maxdamantus | I imagine it wouldn't fry the chip. Only like 0.7 V difference from the nominal maximum voltage of the battery. | 13:01 |
| KotCzarny | hehe | 13:01 |
| KotCzarny | i fried my ssd with 5.35v with prolonged use | 13:01 |
| KotCzarny | i didnt knew sbc was supplying so much at the time | 13:01 |
| KotCzarny | and ssd worked months before it didnt show up after a reboot | 13:02 |
| Maxdamantus | Maybe it could just be used for turning it on. | 13:02 |
| KotCzarny | then adding a small switch+resistor should suffice | 13:02 |
| sicelo | None of my N900s automatically boot | 16:05 |
| sicelo | And yes, N900 is able to run without battery on mainline kernel. Just fine, as long as it's receiving enough power | 16:07 |
| Maxdamantus | It should automatically boot to "play dead" mode. | 21:43 |
| Maxdamantus | So that it can charge at a higher rate than when the device is off. | 21:44 |
| Maxdamantus | When it does that, the backlight is off at the start of the boot, which is why my screenshot shows me figuring out how to turn the backlight on. | 21:44 |
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